Asynchronous clocks are increasingly utilized in technology. For example, many circuits consist of different functional modules that operate at different clock frequencies. It is often necessary to switch the source of a clock line while a circuit is running. Conventionally, the system multiplexes the two different frequency clocks, and controls the multiplexer to select one of the clocks as the clock line.
However, a chance of generating a clock glitch occurs during or soon after a switch between the asynchronous clocks. A glitch on the clock line may be hazardous to the whole system as it may cause metastability in the system.